TEETH AND THEIR VARIATIONS. 



207 



FIG. 06. The last right lower cheek-tooth 

 of a Piy. 



seen from the figure, the cones of all the teeth have 

 now lost the sijaaple form of the earlier species, and 

 have been thrown into " puckers," so that when worn 

 the exposed islands of dentine have an irregular shape 

 with " crinkled " edges. 

 From the ' hillock - like 

 formation of these teeth 

 in the Pig family, the 

 term bunodont (Gr. lou- 

 nos, a hillock) has been 

 proposed for this type of 

 dental structure. In cor- 

 relation with this comparatively simple type of cheek- 

 teeth, it should be mentioned that the Pigs have incisor 

 teeth and large tusks in both jaws : while their feet 

 agree with those of ordi- 

 nary mammals in having 

 the middle metacarpal ancl 

 metatarsal bones (or the 

 bones immediately below the 

 wrist and ankle) separate 

 from one another. 



From the type of tooth 

 represented in Fig. 65, other 

 fossil forms exhibit a com- 

 plete transition to the im- 

 perfect tooth represented in 

 Fig. 67. In addition to the 

 immaterial point of its larger dimensions, it will be 

 noticed that the latter has five cones, a minute cone 



FIG. 67. An imperfect left upper 

 cheek-tooth of an extinct Seleno- 

 dont pip-like animal. 



